Introduction

The 17 gene assay (Oncotype Dx Genomic Prostate Score, GPS) is a validated, biopsy-based commercial gene expression assay that, combined with clinical features, provides an individual estimate of disease aggressiveness at the time of PCa diagnosis. We report interim study results on the impact of GPS on the management of clinically low risk PCa patients in community-based urology practices.

Methods

1,200 patients were prospectively enrolled from 26 sites. For this interim analysis, we report 1 year outcomes in the first 297 patients with valid GPS results. The primary endpoints were GPS’ impact on initial management and persistence on active surveillance (AS) at 1 year post-diagnosis in patients who chose to pursue AS. Rates of AS utilization and persistence in GPS tested patients were compared with a group of 247 patients who did not have genomic testing managed in the same practices (baseline cohort). Descriptive statistics were reported. Analyses were conducted using SAS 9.4.

Results

One-year results were available in 258/297 tested patients (26% NCCN VL, 43% Low and 31% Intermediate). Both utilization and persistence on AS were higher in the GPS-tested cohort (62% vs 40% AS adoption and 89% vs 86% AS persistence) at 1 year. Higher utilization and persistence on AS resulted in a 21% absolute increase in the proportion of men on AS at 1 year post-diagnosis in the GPS tested cohort compared to and baseline (Figure 1). Net increases of patients on AS at 1 year were seen across age groups (59% vs. 41% in >=65yrs, and 51% vs. 29% in <65 yrs), and racial groups (51% vs. 39% in African American, and 55% vs. 33% in all other racial groups).

Conclusions

Patients, especially younger men, and physicians who received GPS were more likely to pursue AS for initial management than untested patients. Overall utilization of AS was 62% higher in GPS tested vs. untested patients at 1 year post-diagnosis. The individual risk refinement provided by genomic testing demonstrates the impact of the GPS in identifying appropriate patients and supporting more AS decisions in clinically low risk PCa.

Funding

Genomic Health